1. Field of the Invention
This invention relates to a tool holder of the type that is adapted to conduct a pressurized liquid coolant therethrough.
2. Prior Art
Tool holders have been used heretofore which have a straight shank that is received in a machine tool, the presence of which blocks the flow of control air to signal the presence of a tool as part of an automatic control circuit.
Further, it has been known heretofore to provide a stop screw on the inner end of the shank of a tool for engaging a surface, such as within a machine tool spindle, such stop screw thus determining the effective length of the tool holder with its tool.
It has been known heretofore to provide a passage through such stop screw and such shank in order to enable the conduction of pressurized liquid coolant to a tool carried by the holder, the tool being adapted to receive such coolant through its shank.
If the coolant-through feature is to be combined with the air-sensing feature, the air pressure could fail to build up and thus cause the control system to malfunction. Accordingly, heretofore, tool holder shanks have been internally machined to accommodate the various parts that make up a check valve assembly, such special components lying between the stop screw and the inner end of the tool. Such a solution to the problem mentioned has been expensive in that specialized internal machining is required for the shank of the tool holder before such check valve components could be assembled therewith, thus increasing the cost of the shank portion of the tool holder.
For the manufacturer of both types of tooling, this circumstance has necessitated the stocking of both types of shank because it is too expensive to provide unneeded machining in shanks that do not need a check valve and therefore both standard and special shanks have been required to meet the demands of whatever the customer requirement might be.
Further, this solution to the problem has resulted in the necessity for providing a substantially increased number of component parts to make up the tool holder assembly.
Further, it has not been possible to utilize the standard tool holder having coolant-through capacity in an application requiring the internal check valve.